This proposal is concerned with mutagenesis and carcinogenesis induced by aromatic polycyclic hydrocarbons which are environmental pollutants. The experiments described will show whether, and how, DNA adducts formed from the proximate carcinogens produce mutations. Our study offers a new approach: we will use the mammalian virus SV40, with its DNA modified in vitro by treatment with the proximate hydrocarbon carcinogen. The modified and characterized SV40 DNA vector will then be studied in infected cells, from which we will learn the molecular nature (base change, insertion, deletion) and location of mutations caused by the hydrocarbon adducts. Our studies will also help to elucidate the role of DNA repair in mutagenesis. We will study both pre- and post-replicative repair and will determine whether the repair process itself is error-prone. A close correlation between mutagenesis and carcinogenesis will be made possible by examining the extent of mutagenesis of SV40 in the same cells in which transformation by the hydrocarbons will be studied. This last approach will also provide a basis for the screening of potential carcinogens.